Panel core constructions



June 10, 1958 D. v. MAZZOCCO PANEL CORE CONSTRUCTIONS Filed July 18, 1955 2 Sheets-Sheet 1 o T m V0 m2 2 m V AB D WMMQMZMM ATTOR/VEKS'.

June 10, 1958 D. v. MAZZOCCO PANEL CORE CONSTRUCTIONS Filed July 18, 1955' 2 Sheets-Sheet 2 ma N Wm. m m I W MN V Z M .D M

not 12.3 2 |l|||l| Y an v muthbm 2t 1 M n Q 440% hwhk m 2's? 3 United States PatentO 2,837,788 PANEL C(lRE CGNSTRUCTIONS Dante V. Mazzocco, Hartsdale, N. Y.

Application July 18, 1955, Serial No. 522,534

-6 Claims. (Cl. 20--91) This invention relates to new and useful improvements in panel core constructions for building unit panels of the type employed in the construction of walls, doors, partitions and the like. Modern building methods look more and more toward prefabrication as a solution to sharply rising costs at the construction site. Panel units which can be assembled by mass production techniques at a central factory and then shipped to the various far flung erection locations are the backbone of this prefabrication method. Such type panels to be satisfactory should be characterized by high strength and rigidity, thereby eliminating the need for additional reinforcing members; lightness of weight so as both to facilitate ease of handling on thejob and to minimize freight charges; and elfective insulating quality so as to avoid the time consuming and expensive task of installing conventional insulation. While numerous types of panel units have heretofore been designed involving one or more of these characteristics in varying degree, each has been subject to certain disadvantages from a commercial standpoint. For example, units of this type formed of two sheets of plywood separated by spacer units or pegs are known. However, such type panels have heretofore lacked the requisite strength and rigidity and have, moreover, been relatively heavy and hence subject to high shipping charges. In such panels the strength and rigidity of the unit is, of course, in large part supplied by the contact between the ends of the pegs and the plywood sheets. That is, for panel sheets of any given size and composition and with other factors being equal, such as the size, number, relative spacing of the pegs, etc., the area of contact between the ends of the pegs and the sheets governs the ultimate rigidity of the panel unit, i. e., the larger the area of contact between peg and sheet, the more rigid the final construction will be. Thus by providing pegs of relatively large cross-sectional area, the requisite rigidity of the panel can be obtained. However, since the pegs themselves contribute in large part to the over-all weight of the unit and since for any given material an increased cross-sectional area of the peg will mean an increased over-all weight of the unit, attempts to provide pegs having a large enough cross-sectional area to provide the requisite rigidity have resulted in panel units which are relatively heavy and, therefore, subject to the aforedescribed resultant disadvantages. Furthermore, the plywood sheets of such panels contribute substantially to the over-all weight of the panel and thus increase the shipping costs.

The present invention overcomes the aforesaid disadvantages by providing an extremely light-weight panel core which can be shipped to the construction sites and there readily. combined with facing members of plywood or sheet metal or such other material as may be desired so as to' form an extremely strong and rigid panelunit having good insulating properties. The panel core of the invention preferably comprises a pair of semi-rigid sheet members made of cardboard or the like which are held apart in spaced relation by a plurality of spacer pins extending between the members with their ends glued, respectively, to each of said members in such manner as to form a base of support between the end of each peg and the panel member which has a larger cross-sectional area than the cross-sectional area of the peg itself. Each of the core sheets is preferably comprised of spaced inner and outer plies of cardboard with the outer ply being substantially flat and the inner ply having formed therein a plurality of raised annular shoulders abutting against said outer ply and glued thereto. Each annular shoulder is provided with inwardly tapering walls which form a frustro-conical pocket adapted to hold a quantity of glue which latter serves to secure in position an end of one of the spacer pegs, as will be hereinafter described. The panel core is comprised of two such sheets arranged with their inner plies facing each other, and their frustroconical pockets aligned, one sheet being held in the desired spaced apart relationship from the other by means of spacer pegs extending therebetween and having their respective ends glued in place in a pocket of each sheet.

A preferred method according to the invention of assembling the panel core comprises feeding the outer ply of a core sheet, that is, a fiat sheet of cardboard of the desired thickness, from a roll, depositing on said sheet a plurality of predetermined masses of glue, spaced apart and symmetrically arranged as desired, and simultaneously and synchronously feeding from a roll, the inner ply of the core sheet with its raised annular shoulders projecting toward and its frustro-conical pockets facing said outer ply. These shoulders and pockets may be preformed in said inner ply by embossing, and it should be understood that they will correspond in number and symmetrical arrangement to the aforesaid glue masses deposited on the outer ply. Said outer and inner plies are then fed through a pair of press rolls, whereupon the glue masses on the outer ply register with and largely fit with the pockets formed in the inner ply, the peripheral portions of each said glue mass being engaged by the annular shoulders of the inner ply, thereby sealing said plies together at a plurality of spaced points throughout their extent, with the remaining areas of the respective plies being in spaced apart relationship, thereby forming an insulating air space as will be described hereinafter. Thereafter two thusly formed core sheets with their inner plies facing each other and their glue containing pockets in alignment are fed through another pair of press rolls and spacer pegs are inserted in position with their ends being forced into the glue pockets. In order to facilitate such entry of the peg ends, the bases of the frustro-conical pockets are preferably pre-weakened by forming circular indentations therein having a diameter corresponding substantially to that of the pegs 13'.

As will be more fully described hereinafter upon subsequent hardening of the glue, each peg end will be firmly anchored by means of a frustro-conically shaped mass of glue to a core sheet, that portion of the glue mass of greatest area being bonded to the outer ply of the sheet. Thus each peg end will, in effect, be provided with a broadened base of support, thereby insuring the desired rigidity without requiring pegs of exceptionally large cross-sectional area.

Such panel cores may, of course, be formed of any desired length, width and thickness depending upon the intended application, be it a wall board, door or the like. Since their cardboard core sheets are much lighter than the conventional plywood, these cores may be shipped with a minimum of freight costs to the various erection sites, and there the contractor can readily transform the same into a finished panel by gluing or otherwise securing to the exterior of said cores plywood sheets or sheet metal or any other desired finishing material. It will be, of

3 course, readily understood that when such outer plywood sheets are thus glued or secured to the core sheets, the spacer pegs are rigidly united with said outer sheets through their frustro-conical glue bases, thereby providing a rigid panel.

Panel cores, according to the invention, are possessed of excellent insulating characteristics in that non-conducting air spaces exist not only between the two core sheets themselves but also between the plies of sheets. Furthermore, when it is desired to additionally enhance the 'cores insulating properties, the opposed faces of the inner plies of each core sheet may be coated with aluminum foil or other highly mirrored finish such as silver ink.

Other and more specific objects, features and advantages of the invention will appear from the detailed description given below taken in conjunction with the accompanying drawings forming a part of this specification and illustrating by way of example, the presently preferred embodiment of the invention.

In the drawings:

Fig. 1 is a fragmentary perspective view showing a preferred form of the panel core of the present invention.

Fig. 2 is an enlarged fragmentary cross-sectional view taken on line 22 of Fig. l and showing the manner in which the spacer pegs are attached to the core sheets.

Fig. 3 is a fragmentary side elevational view, largely schematic, showing the manner in which the inner and outer plies of a core sheet are assembled.

Fig. 4 is a fragmentary side elevational showing of the manner in which the spacer pegs may be inserted between two core sheets and the core thus united.

Fig. 5 is an enlarged fragmentary view showing in perspective a spacer peg in position to be forced into a glue containing core sheet pocket.

Fig. 6 is a fragmentary perspective view of a core according to the invention which has been finished into a rigid panel unit.

Referring now in more detail to the drawings and particularly to Figs. 1 and 2, a panel core 10 is there shown comprising core sheets 11 and 12 secured together in spaced apart relationship by means of a plurality of symmetrically arranged spacer pegs 13. As can be best seen in Fig. 2, each of the core sheets 11 and 12 is formed of outer and inner plies 13 and 14, respectively, which plies may be formed of semi-rigid cardboard having a thickness, for example, of between thirty to forty thousandths of an inch. As shown, the outer layer 13 is flat, while the inner layer 14 has been embossed as at 15 so as to provide a plurality of raised annular shoulders 16 having inwardly tapering walls 17 which form frustroconical pockets 18. These pockets 18 are adapted to receiveand contain a predetermined mass of glue 19, the peripheral portions 20 of which mass of glue serve to adhere the raised shoulder 16 of the inner ply 14 to the outer ply 13. The spacer pegs 13 extend between the core sheets 11 and 12 with their ends 21 projecting into the glue pockets 18. As will be described more in detail hereinafter, these peg ends 21 are inserted into the glue pockets in contact with the glue masses 19 while said glue is still in the viscous state. Upon hardening of the glue, the same will, of course, firmly adhere the pegs 13' to the core sheets 11 and 12, thereby maintaining the latter in the desired spaced relationship. Moreover, in view of the frustro-conical conformation of the pockets 18, upon such solidification of the glue masses 19, the ends of pegs 13 will be in effect provided with enlarged frustroconical bases firmly secured in contact with the outer plies 13 of the core sheets 11 and 12. Thus an area of contact between core sheet and peg end, which is substantially larger than the cross-sectional area of the peg itself will be provided, thereby affording the desired rigidity in a finished panel unit without increasing the over-all weight of the unit by any substantial amount. The spacer pegs 13 may be, of course, formed of jany desired cross-section, but as shown they are circular and 4 hence may comprise conventional dowel pins which are readily available on the market.

Referring now to Figs. 3-5, a preferred method of assembling a panel core 10 of the invention is there shown. There the outer ply 13 of a core sheet is fed from a roll mechanism 25, while the inner ply 14 of a core sheet is fed at a similar speed from another roll mechanism 26. As can be seen in Fig. 3, the outer ply 13 is in the flat condition, while-the inner ply 14 has been embossed so as to have a plurality of raised annular shoulders 16 and frustro-conical glue pockets 18. The bases of these glue pockets have been pre-weakened by providing a circular indentation as at 18' corresponding substantially in diameter to the diameter of the spacer pegs 13 for a purpose which will be hereinafter set forth. T he outer ply 13 is fed past a glue depositing mechanism 27 which may comprise a plurality of cylinders such as 28 and reciprocating plungers such as 29 disposed in spaced apart alignment transversely of the path of travel of the ply 13 and designed to deposit on the surface of said ply a plurality of predetermined masses of glue 19, the number and spacing of said glue masses depending, of course, upon the number, spacing and rate of operation or" the cylinder and plunger mechanism 28, 29. As shown in Fig. 3, the plies 13 and 14 are gradually guided in converging relationship through a pair of driven press rolls 31 and 32. The plies are relatively arranged so that the raised annular shoulders 16 of the inner ply 14 project toward the outer ply 13. It should be, of course, understood that the number and symmetrical arrangement of these raised annular shoulders 16 will, of course, by design correspond to the number and spacing of the glue masses 19 which have been deposited on the outer ply 13. As the two plies pass through the rolls 31 and 32, the glue pockets 13 of the inner ply register with the masses of glue 19, and as the rolls force the two plies into contact with one another, the peripheral portions of each of the glue masses engage the annular shoulders 16 of the inner ply while the bulk of the glue mass is contained within the pockets 18 of the inner ply. At this point the two plies of a core sheet have been thus united while the glue in the pockets 18 is still maintained in the viscous state. At this stage two thusly formed core sheets 11 and 12 with their inner plies 14 facing each other are fed in converging relationship through the pair of press rolls 33, 34 and the spacer pegs 13' are inserted in position. A plurality of these pegs may be carried by a magazine 35 disposed between the converging core sheets and a reciprocating pin pusher and clamp mechanism 36 may be provided so as to eject a peg 13 from the magazine into position between the two core sheets 11 and 12 with the ends of said peg being aligned with the glue pockets 13 provided in saidsheets. With the pegs in this position as the core sheets are forced together under the pressure of the rolls 33 and 34, the ends of the peg 13 are forced through the bases of the glue pockets into contact with the mass of glue contained therein. As mentioned above, in order to facilitate this forceful entry of the spacer pegs through the bases of the glue pockets, said bases are preferably previously indented or otherwise weakened as at 18' along a circular path corresponding substantially in diameter to the diameter of the spacer pegs themselves. Furthermore, these circular indented portions of the glue pocket bases have been additionally pie-weakened by forming a plurality of radial cuts 37 in the cardboard base. These cuts divide the indented portions into a plurality of triangular tabs 38 which will serve to prevent the glue from falling out of the pockets prior to the insertion of the spacer pegs and yet will offer little resistance to the entrance of the pegs under pressure, each tab folding inwardly as shown in Fig 2. It should be understood that while only one peg magazine and peg ejection mechanism 36 has been shown, there are obviously provided a plurality of aligned magazines spaced transversely of the path of travel of 7 building material.

the core sheets through the press rolls 33 and 34, the number and spacing of said magazines being determined by the number of rows of spacer pegs desired in the panel core.

The panel core of the invention as thus formed comprises an extremely lightweight unit which may be readily finished into a complete panel which possesses great strength and rigidity. The coreunits are shipped to the particular erection site and as shown in Fig. 6, a core unit 40 of the same general construction as Fig. of unit 1 may be finished into a complete building panel unit by the simple expedient of gluing plywood sheets 41 and 42 to the outer plies of each of the core sheets 43 and 44. Plywood has been shown, but it should be of course obvious that these external panel unit sheets can consist of sheet metal or any other desired rigid It will be obvious that once such plywood sheets such as 41 and 42 are secured by glue as at 45, 46 to the outer plies of the sheets of the core unit, the spacer pegs are in effect integrally united to the plywood sheets 41 and 42, and said pegs serve to provide a most rigid and very strong building panel unit. It should be further understood that these panel units may be of any desired size, since the cores may be readily mass produced as above described of greatly varying dimensions. sheets may be in the order of 8-ft. lengths and 4-ft. widths, while the spacer pins may be in the order of 4", thereby providing a panel unit having a width corresponding to the ordinary 2 x 4. Similarly, if the core unit is to be used for a door panel, smaller dimensions may be readily provided. Likewise it should be understood that the number and spacing of the pegs 13 will determine in large part the rigidity and strength of the ultimate finished panel unit. Therefore, when a panel unit is desired for heavy stress duty, the pegs will be relatively closely spaced and a large number provided, whereas if only light loads are to be encountered, any desired number of the pegs may be omitted and the spacing correspondingly rearranged, thereby providing an even lighter unit which is still strong enough for the purpose desired.

As has been mentioned above, the panel core of the invention provides excellent insulation for the finished panel unit due to the presence of the nonconducting air spaces 50 and 51' provided between the inner and outer plies of each of the core sheets 11 and 12 and the even larger non-conducting air space 52 provided between the inner plies of the twosheets (Fig. 2). However, the insulation characteristic of this core unit may be even further enhanced, if desired, by providing a mirror-like film or layer of material such as aluminum foil or silver ink53, 54 adhered to the opposed faces of the inner plies of the core sheets. These layers of aluminum foil or the like practically eliminate any transfer of radiant heat throughout the panel. Moreover, since the interior of the panel is completely open, all portions of each of the aluminum foil sheets 53 and 54 being in continuous contact, any heat or cold which may pass through to said foil sheets is immediately dissipated as it spreads throughout the entire extent of the layer of conducting material.

Although certain particular embodiments of the invention are herein disclosed for purposes of explanation,

various further modifications thereof, after study of this specification, will be apparent to those skilled in the art to which the invention pertains. Reference should accordingly be had to the appended claims in determining the scope of the invention.

' What is claimed and desired to be secured by Letters Patent is:

1. A panel core construction comprising a pair of semirigid core sheets and a plurality of spacer pegs extending Thus if a wall board core is desired, the core between said core sheets and adapted to maintain the latter-in spaced apart relationship, the ends of each of said spacer pegs being bonded to said core sheets by a t 3 means of glue masses, each said glue mass having a larger cross-sectional area-than the. cross-sectional area of the spacer pegs, said core sheet being each formed of spaced apart inner and outer plies with the inner plies of each sheet facing each other and a layer of metal foil adhered to the opposed faces of said inner plies.

2. A panel core construction comprising a pair of spaced apart core sheets, each core sheet being formed of spaced apart inner and outer plies with one of said plies having a plurality of glue receiving pockets formed therein and a mass of glue positioned in each said pocket, and a plurality of spacer pegs extending between said core sheets and adapted to maintain the sheets in spaced apart relationship, the respective ends of each peg being anchored in a glue mass of each of the core sheets.

3. A panel core construction comprising a pair of core sheets, a plurality of spacer pegs extending between said core sheets and adapted to maintain the latter in spaced apart relationship, the ends of each of said spacer pegs being bonded to said core sheets by means of glue masses, each said glue mass having a larger cross-sectional area than the cross-sectional area of the spacer pegs.

4. A method of assembling a panel core which comprises the steps of forming a core sheet by feeding an outer ply of semi-rigid material which is in the flat condition from roll means, depositing on said ply a plurality of predetermined masses of glue in spaced apart and symmetrical arrangement and synchronously feeding from another roll means an inner ply of semi-rigid material having a plurality of raised annular shoulders and frustroconical pockets formed therein, the number and symmetrical arrangement of said pockets conforming to the number and symmetrical arrangement of the glue masses deposited on said outer ply, applying pressure to said ply members Whereby the same are forced together, the peripheral portions of each glue mass carried by the outer ply being engaged by the annular shoulders formed on the inner ply, thereby sealing said plies together at a plurality of spaced points with the glue masses being contained within said pockets, and the remaining areas of the respective plies being in spaced apart relationship, then forming a second core sheet in similar manner, feeding the two thusly formed core sheets with their inner plies facing each other and their glue containing pockets in alignment through a pressure applying means and forcing spacer pegs into position extending between aligned glue pockets of each said core sheet.

5. A method of assembling a panel core which comprises the steps of forming a core sheet by feeding two plies of semi-rigid material into converging relationship, one ply being in the flat condition and the second ply having a plurality of raised annular shoulders and glue receiving pockets formed therein, depositing a plurality of glue masses on the ply which is in the flat condition, the number and symmetrical arrangement of said glue masses conforming to the number and symmetrical arrangement of the pockets formed in said second ply, applying pressure to said ply members whereby the same are forced together, the peripheral portions of each glue mass carried by the one ply being engaged by the annular shoulders formed on the other ply, thereby sealing said plies together at a plurality of spaced points with the glue masses being contained within said pockets, then forming a second core sheet in similar manner, feeding the two thusly formed core sheets with the plies having the pockets formed therein facing each other and with the pockets of the respective sheets in alignment through a pressure applying means and forcing spacer pegs into position extending between aligned glue pockets of each said core sheet.

6. A prefabricated panel unit comprising two rigid sheets of construction material each glued to one side of the exterior of a panel core which comprises a pair of spaced apart semi-rigid core sheet, each core sheet being formed of inner and outer plies with one of said plies having a plurality of glue receiving pockets formed therein and a mass of glue positioned in each of said pockets, and a plurality of spacer pegs extending between said core sheetswith their ends, respectively, anchored in one of the masses of glue contained in each core sheet.

References Cited in the file of this patent UNITED STATES PATENTS Le Gall Aug. 29, 1939 Davis Sept. 25, 1945 Simonton et a1 Aug. 17, 1948 Rundquist Aug. 23, 1949 Prase Aug. 18, 1953 Waldherr Feb. 9 1954 

